A machine of this kind is disclosed in the Specification of British Patent No. GB-B-2214198. According to that Specification descending warp threads 12 pass through respective wire guides 34 which, with the cylindrical surface of the knitting head to which they are secured, form individual, approximately sector-shaped apertures above the needle tricks. The descending warp threads are deflected by the apertures on their way to the respective needle tricks and they are moved across the wire guides by the presser plate or placing element 38 in order to be engaged by the needle hooks.
The provision of the guides 34 limits the number of needle tricks which can be provided in a given cylinder. The present Applicants have discovered that if warp threads approach the cylinder at an appropriate angle and if the presser plate is appropriately shaped and positioned there is no necessity to surround each warp thread with such a guide. Dispensing with these guides permits the use of up to twice as many needles in the same machine, thus permitting the manufacture of a more closely or densely knit product without any detriment to the speed and efficiency of the operation. The machine of the present invention is simpler, utilises less components and is easier to maintain.
A long-standing problem associated with the use of such machines is that as a needle rises sufficiently for its latch to cast off onto the stem of the needle the loop of warp thread which has just been formed the latch will tend to close with great violence before it is intended to close, i.e. before it is closed by the said loop as the needle later descends. Due to the high speed of the machine and the energy accumulated in the latch before it is released the latter can bounce between closed and open positions and in the worst case may be closed when a warp thread is passed around the needle by the presser plate, so that a stitch cannot be formed.